Research On Pelvis-control Mechanism Of Gait Training Robot

Illness, aging, Physical Trauma and accidents are factors leading to various level harms to people's limb and making people suffering differently. So the assistant training robot helping to recover from this suffering is a hot research topic in the academic community.Gait training robot is mainly used to help human beings regain the ability of working. Now most research work focus on lower limbs, ignoring a significant factor:the pelvis. Human's pelvis, which connects lumbar vertebra and legs, plays an important role in motion, so harmonious pelvis movement is the key point of mastering right gait. Clinical practices proved that patient's lower limb walking ability could be proved by pelvis training. Consequently, it's necessary and reasonable to provide the patient with the pelvis training treatment during the process of gait training.This paper presents the overall design of pelvic control mechanism with 4-DOF based on the current motion trajectory research of the human pelvis. And the platform for pelvis training system is designed. In addition, a suspension system for supporting the gravity by riding is proposed.Robot concerned in this paper only has three acutators while DOF is four, which means this robot is categorized into the under-actuated system. Therefore two constraint approaches, no fully constraints on the middle spring and half driven constraint on the rope actuators in the direction of free motion, is adopted to solve the under-actuator problem. Those two approaches is verified by the simulation using the SimMechanics. Based on both theoretical analysis and semi-physical simulation based on the platform of dSPACE real-time simulation system, the theory is proven and approaches are effective. Also the results of the experimental work in controling the pelvic-driven mechanism show that the system is stable and the track errors are in the allowance, which give the rationality and correctness of proposed pelvic control mechanism.